berlinpro an erl demonstration facility at the helmholtz zentrum berlin
TRANSCRIPT
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Main components:
100MeV, 100mA beam Small emittance, rel. short bunches High current: to address needs of storage ring users Show energy recoveryExplore limits of ERL (multiturn, injection energy)Show different operational modes: high current (100mA, 2ps), short pulses (10mA, 100fs), ??, => superiority of the ERL concept to storage rings
BERLinPro: ERL demonstration facility to prepare the ground for a few GeV ERL @ Berlin-Adlershof
Goal:
•SC-RF gun•Booster module – Cornell development with minor modifications•Merger: C-chicane, 4 rectangular dipoles•Linac: based on Tesla technology, modified for high current•Return arc: TBA•Second loop option
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Finances and time table :
• ‚go ahead‘ for gun development• R&D money for gun development secured• Further approval process for entire budget
2010 beam from 1.6 cell gun cavity in HoBiCaTConceptual design
2011Technical layout (TDR)
5 years after approval: first recirculated electrons
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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GUN DEVELOPMENT
SRF Gun
Return Arc
Merger SectionMain Linac SRF Module
Spent Beam
Beam Dump
SRF Booster
1.5 MeV
5-10 MeV
100 MeV
Beam Manipulation Undulator tests
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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BERLinPro gun: Staged approach
A high brightness source which can deliver high average current and short pulses.
Stage 1-Beam Dynamics: Produce beam with cold gun in existing HoBiCaT cryomodule.
Nb cavity with Pb-coated cathode (J. Sekutowicz & Co), UV laser (MBI), sc solenoid and beam diagnostics.
Stage 2-Cathode integration: Extend HoBiCaT bunker, new cryomodule, cathode preparation infrastructure. Produce 1 to 10 mA with CsK2Sb cathode, green laser (MBI).
In parallel, test gun cavities and new RF coupler (>100kW) in HoBiCaT.
Stage 3-High current operation: Build SRF gun for BERLinPro (high rep. rate) F
rom
J.
Sekuto
wic
z, P
roc.
of
PA
C0
9
Courtesy of Thorsten Kamps
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Stage 1 setup in HoBiCaT
1.6 cell cavity, sc-solenoid,Helium supply
Stage 1 diagnostic beam line
View screens, stripline, current monitor, emittance measurement, energy measurement
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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HoBiCat preparations:
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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MERGER DESIGN CONSIDERATIONS
SRF Gun
Return Arc
Merger SectionMain Linac SRF Module
Spent Beam
Beam Dump
SRF Booster
1.5 MeV
5-10 MeV
100 MeV
Beam Manipulation Undulator tests
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Zigzag chicane: (Brookhaven)
Space charge forces: compatible with emittance compensation scheme
Higher order dispersion: intrinsically cancelled by C-chicane with rectangular magnets
• equal focussing in both planes• 2. order dispersion not 0• Small trajectory displacement• Fixed relation D1/D2• „Geometrically challenging“(vertical construction in Brookhaven)
• Easier to incorporate in machine• Flexible drift lengths• Offset adjustable by drift length• Vertical focussing
C-chicane:
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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ASTRA: Emittance for Zigzag / C- chicane for increasing bunch charge and different energy spread (correlated)
C-chicane
Zigzag
Gaussian bunch: x,y = 1.0 mrad x,y = 1.0 mm z = 1.0 mm x,y = 20.0 m x,y = 0
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Bunch lengthening in merger due to energy spread / space charge
Effect is reduced when goingto 10 MeV injection energy.
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Emittance vrs. bunch length
Gaussian bunch:E = 10 MeV x,y = 1.0 mrad x,y = 1.0 mm x,y = 20.0 m x,y = 0E = 20keV
Emittance depends strongly on bunch length:
Charge z Compression77pC 6ps 3 or more10pC 1ps 10 or more77pC
10pC
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Lambertson magnet: Good idea??
Last merger dipole deflects high energy beam by up to 4°
=> extra chicane necessary
Lambertson: High energy beam travels infield free region, injected low energy beam runs parallel
Lambertson would reduce 4° to less than 0.14°, which is rather an orbit correction
By Lars-Johan Lindgren, MAX-lab
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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L1
d
d \ L2 0.4m 0.8m 1.2m
10mm 1.4 0.7 0.5
20mm 2.9 1.4 0.7
30mm 4.3 2.1 1.4
[°] as a function of d, L1
0.025rad = 1.432deg.
High energy beam deflected by 1/10: 0.14° mean 2.5cm offset after 10m linacSteering for HE beam is necessaryPlace for HE optical elements before Lambertson
SteererLast merger dipoleLambertson?
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Linac:
SRF Gun
Return Arc
Merger SectionMain Linac SRF Module
Spent Beam
Beam Dump
SRF Booster
1.5 MeV
5-10 MeV
100 MeV
Beam Manipulation Undulator tests
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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100 MeV Linac:
•1.3 GHz•Start with multicell TESLA and adapt this for CW and high current •Single cryomodule with 6-7 cavities•7 cells/cavity (?)•Application „Verbundforschungsantrag“: federal funding for a collaboration
with Univ. Rostock and Dortmund for the calculation of HOM
Options for HOMs: Ferrite loads, waveguide dampers•HoBiCaT test
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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RECIRCULATOR - ARC
SRF Gun
Return Arc
Merger SectionMain Linac SRF Module
Spent Beam
Beam Dump
SRF Booster
1.5 MeV
5-10 MeV
100 MeV
Beam Manipulation Undulator tests
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Path length management:
•Short bunches require pathlength adjustment•Second loop option:
100MeV: 1. turn: L=(n+1/2) rf
200MeV: 1. turn: L= n rf (rf/2=12cm)•Variable injection energy alters path length in merger & splitter for HE beam
20o bend @ 5-20MeV = 1-4o @ 100MeV => 0.5cm
t
EE = E0 cos (t +0)
X = – 2 0
=
head with higher Egives compression with “normal” arc R56
chirp at decelerationdoubles inacceptableenergy spread
L = 2 rf =2-3cm deg.
Courtesy of Michael Abo-Bakr
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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3 Approaches to pathlength adjustment:1 - Brookhaven: Build arc on sledge, mechanical adjustment
very precise expensive slow
2 - C-chicanelong @ 100MeV: 2-3mCSR – bunches are short
3 - Incorporate into the arc
1
0
0
1
K
SB
X0
X1
D0
D
1,3[°] 2[°] K[°] xmax/cm
60 60 4.8 6.3
45 90 2.9 4.5
Angle and offset for 6cm additional pathlength
Courtesy of Michael Abo-Bakr
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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Radiation safety requirements:
Different ‚league‘ than storage ringsDrive costs =>drive beamloss requirements Permissable beamloss:<1e-5?
=> Too little space for shielding above ground => Consider construction underground
reduced shielding, vibrations and temperature fluctuations at comparable costs
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
21
BESSY IIBESSY II
Cryogenic plant
March, 1st, 2010, Bettina Kuske, FLS 2010, SLAC, USA
BERLinPro: An ERL demonstration facility at the HELMHOLTZ ZENTRUM BERLIN
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